Pros
Many of the people in Stamford are very competent and diligent, There is very good Interactions between departments and you can learn new ideas from each area. Stamford has state of the art technology. Work-life balance is very good. There will be long days, but the trade off is management will allow you to work at home every now and then.
Cons
As of now the bank in the US overall is still shrinking, so an increase in compensation won't happen for most people. Unfortunately this is the same for career opportunities. Its not clear what plans Senior Management has for the US besides trying to IPO their largest US subsidiary, Citizensbank, and the reduction of personnel on the investment bank side. RBS is 84% owned by the UK Taxpayers, so UK management listens very closely to what the government wants the bank to do. In turn UK management tells the US management what the strategy of the day, month or year will be.